Considerable work has been performed in the field of adipocyte differentiation in an effort to delineate the specific factors and processes involved. Fat cells or adipocytes are a specialized cell type that synthesizes and stores fat (triglycerides) in periods of nutritional abundance, and hydrolyze these fats when needed to meet demand for energy. The size and distribution of adipose tissue stores in humans and animals clearly influences metabolism and the development of diseases including, but not limited to obesity and diabetes.
The development of mature adipocytes from precursor cells, a process known as differentiation has been widely studied. Most adipocyte differentiation occurs shortly before or after birth, but further differentiation can occur at any time during life in response to various hormonal and nutritional signals.
A few key proteins that are expressed early in the process of differentiation and are required for adipocyte development have been identified. These include the nuclear hormone receptor peroxisome proliferator-activated receptor γ (PPARγ) and CAAT/enhancer binding protein α (C/EBPα). It is known that these proteins function as transcription activators to induce the expression of genes required for conversion of precursor cells into mature adipocytes. However, many aspects of the regulation and function of these proteins have not been delineated. It is known that proteins such as PPARγ and C/EBPα function in complexes with other protein factors, known as co-activators, to effect transcription.